After successfully compiling the project in Xcode 6, I am unable to run it in the simulator with the above mentioned message. I did all the possible research, tried everything and still no advances.
I am not working with swift, neither I use widgets or extensions, so please do not suggest solutions caused by these as can be seen in similar questions.
If someone found a possible cause (or solution!!) other than these, please help. Thanks
"Reset Content and Settings" from iOS Simutalor menu options and launching simulator after Quitting solved my issue.